Java tutorial
/* Jackson JSON-processor. * * Copyright (c) 2007- Tatu Saloranta, tatu.saloranta@iki.fi */ package com.fasterxml.jackson.core; import java.io.*; import java.math.BigDecimal; import java.math.BigInteger; import com.fasterxml.jackson.core.io.CharacterEscapes; /** * Base class that defines public API for writing JSON content. * Instances are created using factory methods of * a {@link JsonFactory} instance. * * @author Tatu Saloranta */ public abstract class JsonGenerator implements Closeable, Flushable, // as of 2.1 Versioned { /** * Enumeration that defines all togglable features for generators. */ public enum Feature { /** * Feature that determines whether generator will automatically * close underlying output target that is NOT owned by the * generator. * If disabled, calling application has to separately * close the underlying {@link OutputStream} and {@link Writer} * instances used to create the generator. If enabled, generator * will handle closing, as long as generator itself gets closed: * this happens when end-of-input is encountered, or generator * is closed by a call to {@link JsonGenerator#close}. *<p> * Feature is enabled by default. */ AUTO_CLOSE_TARGET(true), /** * Feature that determines what happens when the generator is * closed while there are still unmatched * {@link JsonToken#START_ARRAY} or {@link JsonToken#START_OBJECT} * entries in output content. If enabled, such Array(s) and/or * Object(s) are automatically closed; if disabled, nothing * specific is done. *<p> * Feature is enabled by default. */ AUTO_CLOSE_JSON_CONTENT(true), /** * Feature that determines whether JSON Object field names are * quoted using double-quotes, as specified by JSON specification * or not. Ability to disable quoting was added to support use * cases where they are not usually expected, which most commonly * occurs when used straight from Javascript. *<p> * Feature is enabled by default (since it is required by JSON specification). */ QUOTE_FIELD_NAMES(true), /** * Feature that determines whether "exceptional" (not real number) * float/double values are output as quoted strings. * The values checked are Double.Nan, * Double.POSITIVE_INFINITY and Double.NEGATIVE_INIFINTY (and * associated Float values). * If feature is disabled, these numbers are still output using * associated literal values, resulting in non-conformant * output. *<p> * Feature is enabled by default. */ QUOTE_NON_NUMERIC_NUMBERS(true), /** * Feature that forces all Java numbers to be written as JSON strings. * Default state is 'false', meaning that Java numbers are to * be serialized using basic numeric serialization (as JSON * numbers, integral or floating point). If enabled, all such * numeric values are instead written out as JSON Strings. *<p> * One use case is to avoid problems with Javascript limitations: * since Javascript standard specifies that all number handling * should be done using 64-bit IEEE 754 floating point values, * result being that some 64-bit integer values can not be * accurately represent (as mantissa is only 51 bit wide). *<p> * Feature is disabled by default. */ WRITE_NUMBERS_AS_STRINGS(false), /** * Feature that determines whether {@link java.math.BigDecimal} entries are * serialized using {@link java.math.BigDecimal#toPlainString()} to prevent * values to be written using scientific notation. *<p> * Feature is disabled by default, so default output mode is used; this generally * depends on how {@link BigDecimal} has been created. * * @since 2.3 */ WRITE_BIGDECIMAL_AS_PLAIN(false), /** * Feature that specifies that calls to {@link #flush} will cause * matching <code>flush()</code> to underlying {@link OutputStream} * or {@link Writer}; if disabled this will not be done. * Main reason to disable this feature is to prevent flushing at * generator level, if it is not possible to prevent method being * called by other code (like <code>ObjectMapper</code> or third * party libraries). *<p> * Feature is enabled by default. */ FLUSH_PASSED_TO_STREAM(true), /** * Feature that specifies that all characters beyond 7-bit ASCII * range (i.e. code points of 128 and above) need to be output * using format-specific escapes (for JSON, backslash escapes), * if format uses escaping mechanisms (which is generally true * for textual formats but not for binary formats). *<p> * Feature is disabled by default. */ ESCAPE_NON_ASCII(false), ; private final boolean _defaultState; private final int _mask; /** * Method that calculates bit set (flags) of all features that * are enabled by default. */ public static int collectDefaults() { int flags = 0; for (Feature f : values()) { if (f.enabledByDefault()) { flags |= f.getMask(); } } return flags; } private Feature(boolean defaultState) { _mask = (1 << ordinal()); _defaultState = defaultState; } public boolean enabledByDefault() { return _defaultState; } public int getMask() { return _mask; } } /* /********************************************************** /* Configuration /********************************************************** */ /** * Object that handles pretty-printing (usually additional * white space to make results more human-readable) during * output. If null, no pretty-printing is done. */ protected PrettyPrinter _cfgPrettyPrinter; /* /********************************************************** /* Construction, initialization /********************************************************** */ protected JsonGenerator() { } /** * Method that can be called to set or reset the object to * use for writing Java objects as JsonContent * (using method {@link #writeObject}). * * @return Generator itself (this), to allow chaining */ public abstract JsonGenerator setCodec(ObjectCodec oc); /** * Method for accessing the object used for writing Java * object as Json content * (using method {@link #writeObject}). */ public abstract ObjectCodec getCodec(); /** * Method to call to make this generator use specified schema. * Method must be called before generating any content, right after instance * has been created. * Note that not all generators support schemas; and those that do usually only * accept specific types of schemas: ones defined for data format this generator * produces. *<p> * If generator does not support specified schema, {@link UnsupportedOperationException} * is thrown. * * @param schema Schema to use * * @throws UnsupportedOperationException if generator does not support schema */ public void setSchema(FormatSchema schema) { throw new UnsupportedOperationException("Generator of type " + getClass().getName() + " does not support schema of type '" + schema.getSchemaType() + "'"); } /** * Method for accessing Schema that this parser uses, if any. * Default implementation returns null. * * @since 2.1 */ public FormatSchema getSchema() { return null; } /** * Method that can be used to verify that given schema can be used with * this generator (using {@link #setSchema}). * * @param schema Schema to check * * @return True if this generator can use given schema; false if not */ public boolean canUseSchema(FormatSchema schema) { return false; } /** * Accessor for finding out version of the bundle that provided this generator instance. */ @Override public abstract Version version(); /** * Method that can be used to get access to object that is used * as target for generated output; this is usually either * {@link OutputStream} or {@link Writer}, depending on what * generator was constructed with. * Note that returned value may be null in some cases; including * case where implementation does not want to exposed raw * source to caller. * In cases where output has been decorated, object returned here * is the decorated version; this allows some level of interaction * between users of generator and decorator object. *<p> * In general use of this accessor should be considered as * "last effort", i.e. only used if no other mechanism is applicable. */ public Object getOutputTarget() { return null; } /** * Method that allows overriding String used for separating root-level * JSON values (default is single space character) * * @param sep Separator to use, if any; null means that no separator is * automatically added * * @since 2.1 */ public JsonGenerator setRootValueSeparator(SerializableString sep) { throw new UnsupportedOperationException(); } /* /********************************************************** /* Public API, configuration /********************************************************** */ /** * Method for enabling specified parser features: * check {@link Feature} for list of available features. * * @return Generator itself (this), to allow chaining */ public abstract JsonGenerator enable(Feature f); /** * Method for disabling specified features * (check {@link Feature} for list of features) * * @return Generator itself (this), to allow chaining */ public abstract JsonGenerator disable(Feature f); /** * Method for enabling or disabling specified feature: * check {@link Feature} for list of available features. * * @return Generator itself (this), to allow chaining */ public final JsonGenerator configure(Feature f, boolean state) { if (state) { enable(f); } else { disable(f); } return this; } /** * Method for checking whether given feature is enabled. * Check {@link Feature} for list of available features. */ public abstract boolean isEnabled(Feature f); /* /********************************************************** /* Configuring generator /********************************************************** */ /** * Method for setting a custom pretty printer, which is usually * used to add indentation for improved human readability. * By default, generator does not do pretty printing. *<p> * To use the default pretty printer that comes with core * Jackson distribution, call {@link #useDefaultPrettyPrinter} * instead. * * @return Generator itself (this), to allow chaining */ public JsonGenerator setPrettyPrinter(PrettyPrinter pp) { _cfgPrettyPrinter = pp; return this; } /** * Accessor for checking whether this generator has a configured * {@link PrettyPrinter}; returns it if so, null if none configured. * * @since 2.1 */ public PrettyPrinter getPrettyPrinter() { return _cfgPrettyPrinter; } /** * Convenience method for enabling pretty-printing using * the default pretty printer * ({@link com.fasterxml.jackson.core.util.DefaultPrettyPrinter}). * * @return Generator itself (this), to allow chaining */ public abstract JsonGenerator useDefaultPrettyPrinter(); /** * Method that can be called to request that generator escapes * all character codes above specified code point (if positive value); * or, to not escape any characters except for ones that must be * escaped for the data format (if -1). * To force escaping of all non-ASCII characters, for example, * this method would be called with value of 127. *<p> * Note that generators are NOT required to support setting of value * higher than 127, because there are other ways to affect quoting * (or lack thereof) of character codes between 0 and 127. * Not all generators support concept of escaping, either; if so, * calling this method will have no effect. *<p> * Default implementation does nothing; sub-classes need to redefine * it according to rules of supported data format. * * @param charCode Either -1 to indicate that no additional escaping * is to be done; or highest code point not to escape (meaning higher * ones will be), if positive value. */ public JsonGenerator setHighestNonEscapedChar(int charCode) { return this; } /** * Accessor method for testing what is the highest unescaped character * configured for this generator. This may be either positive value * (when escaping configuration has been set and is in effect), or * 0 to indicate that no additional escaping is in effect. * Some generators may not support additional escaping: for example, * generators for binary formats that do not use escaping should * simply return 0. * * @return Currently active limitation for highest non-escaped character, * if defined; or -1 to indicate no additional escaping is performed. */ public int getHighestEscapedChar() { return 0; } /** * Method for accessing custom escapes factory uses for {@link JsonGenerator}s * it creates. */ public CharacterEscapes getCharacterEscapes() { return null; } /** * Method for defining custom escapes factory uses for {@link JsonGenerator}s * it creates. */ public JsonGenerator setCharacterEscapes(CharacterEscapes esc) { return this; } /* /********************************************************** /* Public API, write methods, structural /********************************************************** */ /** * Method for writing starting marker of a JSON Array value * (character '['; plus possible white space decoration * if pretty-printing is enabled). *<p> * Array values can be written in any context where values * are allowed: meaning everywhere except for when * a field name is expected. */ public abstract void writeStartArray() throws IOException, JsonGenerationException; /** * Method for writing closing marker of a JSON Array value * (character ']'; plus possible white space decoration * if pretty-printing is enabled). *<p> * Marker can be written if the innermost structured type * is Array. */ public abstract void writeEndArray() throws IOException, JsonGenerationException; /** * Method for writing starting marker of a JSON Object value * (character '{'; plus possible white space decoration * if pretty-printing is enabled). *<p> * Object values can be written in any context where values * are allowed: meaning everywhere except for when * a field name is expected. */ public abstract void writeStartObject() throws IOException, JsonGenerationException; /** * Method for writing closing marker of a JSON Object value * (character '}'; plus possible white space decoration * if pretty-printing is enabled). *<p> * Marker can be written if the innermost structured type * is Object, and the last written event was either a * complete value, or START-OBJECT marker (see JSON specification * for more details). */ public abstract void writeEndObject() throws IOException, JsonGenerationException; /** * Method for writing a field name (JSON String surrounded by * double quotes: syntactically identical to a JSON String value), * possibly decorated by white space if pretty-printing is enabled. *<p> * Field names can only be written in Object context (check out * JSON specification for details), when field name is expected * (field names alternate with values). */ public abstract void writeFieldName(String name) throws IOException, JsonGenerationException; /** * Method similar to {@link #writeFieldName(String)}, main difference * being that it may perform better as some of processing (such as * quoting of certain characters, or encoding into external encoding * if supported by generator) can be done just once and reused for * later calls. *<p> * Default implementation simple uses unprocessed name container in * serialized String; implementations are strongly encouraged to make * use of more efficient methods argument object has. */ public abstract void writeFieldName(SerializableString name) throws IOException, JsonGenerationException; /* /********************************************************** /* Public API, write methods, text/String values /********************************************************** */ /** * Method for outputting a String value. Depending on context * this means either array element, (object) field value or * a stand alone String; but in all cases, String will be * surrounded in double quotes, and contents will be properly * escaped as required by JSON specification. */ public abstract void writeString(String text) throws IOException, JsonGenerationException; /** * Method for outputting a String value. Depending on context * this means either array element, (object) field value or * a stand alone String; but in all cases, String will be * surrounded in double quotes, and contents will be properly * escaped as required by JSON specification. */ public abstract void writeString(char[] text, int offset, int len) throws IOException, JsonGenerationException; /** * Method similar to {@link #writeString(String)}, but that takes * {@link SerializableString} which can make this potentially * more efficient to call as generator may be able to reuse * quoted and/or encoded representation. *<p> * Default implementation just calls {@link #writeString(String)}; * sub-classes should override it with more efficient implementation * if possible. */ public abstract void writeString(SerializableString text) throws IOException, JsonGenerationException; /** * Method similar to {@link #writeString(String)} but that takes as * its input a UTF-8 encoded String that is to be output as-is, without additional * escaping (type of which depends on data format; backslashes for JSON). * However, quoting that data format requires (like double-quotes for JSON) will be added * around the value if and as necessary. *<p> * Note that some backends may choose not to support this method: for * example, if underlying destination is a {@link java.io.Writer} * using this method would require UTF-8 decoding. * If so, implementation may instead choose to throw a * {@link UnsupportedOperationException} due to ineffectiveness * of having to decode input. */ public abstract void writeRawUTF8String(byte[] text, int offset, int length) throws IOException, JsonGenerationException; /** * Method similar to {@link #writeString(String)} but that takes as its input * a UTF-8 encoded String which has <b>not</b> been escaped using whatever * escaping scheme data format requires (for JSON that is backslash-escaping * for control characters and double-quotes; for other formats something else). * This means that textual JSON backends need to check if value needs * JSON escaping, but otherwise can just be copied as is to output. * Also, quoting that data format requires (like double-quotes for JSON) will be added * around the value if and as necessary. *<p> * Note that some backends may choose not to support this method: for * example, if underlying destination is a {@link java.io.Writer} * using this method would require UTF-8 decoding. * In this case * generator implementation may instead choose to throw a * {@link UnsupportedOperationException} due to ineffectiveness * of having to decode input. */ public abstract void writeUTF8String(byte[] text, int offset, int length) throws IOException, JsonGenerationException; /* /********************************************************** /* Public API, write methods, binary/raw content /********************************************************** */ /** * Method that will force generator to copy * input text verbatim with <b>no</b> modifications (including * that no escaping is done and no separators are added even * if context [array, object] would otherwise require such). * If such separators are desired, use * {@link #writeRawValue(String)} instead. *<p> * Note that not all generator implementations necessarily support * such by-pass methods: those that do not will throw * {@link UnsupportedOperationException}. */ public abstract void writeRaw(String text) throws IOException, JsonGenerationException; /** * Method that will force generator to copy * input text verbatim with <b>no</b> modifications (including * that no escaping is done and no separators are added even * if context [array, object] would otherwise require such). * If such separators are desired, use * {@link #writeRawValue(String)} instead. *<p> * Note that not all generator implementations necessarily support * such by-pass methods: those that do not will throw * {@link UnsupportedOperationException}. */ public abstract void writeRaw(String text, int offset, int len) throws IOException, JsonGenerationException; /** * Method that will force generator to copy * input text verbatim with <b>no</b> modifications (including * that no escaping is done and no separators are added even * if context [array, object] would otherwise require such). * If such separators are desired, use * {@link #writeRawValue(String)} instead. *<p> * Note that not all generator implementations necessarily support * such by-pass methods: those that do not will throw * {@link UnsupportedOperationException}. */ public abstract void writeRaw(char[] text, int offset, int len) throws IOException, JsonGenerationException; /** * Method that will force generator to copy * input text verbatim with <b>no</b> modifications (including * that no escaping is done and no separators are added even * if context [array, object] would otherwise require such). * If such separators are desired, use * {@link #writeRawValue(String)} instead. *<p> * Note that not all generator implementations necessarily support * such by-pass methods: those that do not will throw * {@link UnsupportedOperationException}. */ public abstract void writeRaw(char c) throws IOException, JsonGenerationException; /** * Method that will force generator to copy * input text verbatim with <b>no</b> modifications (including * that no escaping is done and no separators are added even * if context [array, object] would otherwise require such). * If such separators are desired, use * {@link #writeRawValue(String)} instead. *<p> * Note that not all generator implementations necessarily support * such by-pass methods: those that do not will throw * {@link UnsupportedOperationException}. *<p> * The default implementation delegates to {@link #writeRaw(String)}; * other backends that support raw inclusion of text are encouraged * to implement it in more efficient manner (especially if they * use UTF-8 encoding). * * @since 2.1 */ public void writeRaw(SerializableString raw) throws IOException, JsonGenerationException { writeRaw(raw.getValue()); } /** * Method that will force generator to copy * input text verbatim without any modifications, but assuming * it must constitute a single legal JSON value (number, string, * boolean, null, Array or List). Assuming this, proper separators * are added if and as needed (comma or colon), and generator * state updated to reflect this. */ public abstract void writeRawValue(String text) throws IOException, JsonGenerationException; public abstract void writeRawValue(String text, int offset, int len) throws IOException, JsonGenerationException; public abstract void writeRawValue(char[] text, int offset, int len) throws IOException, JsonGenerationException; /** * Method that will output given chunk of binary data as base64 * encoded, as a complete String value (surrounded by double quotes). * This method defaults *<p> * Note: because Json Strings can not contain unescaped linefeeds, * if linefeeds are included (as per last argument), they must be * escaped. This adds overhead for decoding without improving * readability. * Alternatively if linefeeds are not included, * resulting String value may violate the requirement of base64 * RFC which mandates line-length of 76 characters and use of * linefeeds. However, all {@link JsonParser} implementations * are required to accept such "long line base64"; as do * typical production-level base64 decoders. * * @param b64variant Base64 variant to use: defines details such as * whether padding is used (and if so, using which character); * what is the maximum line length before adding linefeed, * and also the underlying alphabet to use. */ public abstract void writeBinary(Base64Variant b64variant, byte[] data, int offset, int len) throws IOException, JsonGenerationException; /** * Similar to {@link #writeBinary(Base64Variant,byte[],int,int)}, * but default to using the Jackson default Base64 variant * (which is {@link Base64Variants#MIME_NO_LINEFEEDS}). */ public void writeBinary(byte[] data, int offset, int len) throws IOException, JsonGenerationException { writeBinary(Base64Variants.getDefaultVariant(), data, offset, len); } /** * Similar to {@link #writeBinary(Base64Variant,byte[],int,int)}, * but assumes default to using the Jackson default Base64 variant * (which is {@link Base64Variants#MIME_NO_LINEFEEDS}). Also * assumes that whole byte array is to be output. */ public void writeBinary(byte[] data) throws IOException, JsonGenerationException { writeBinary(Base64Variants.getDefaultVariant(), data, 0, data.length); } /** * Similar to {@link #writeBinary(Base64Variant,InputStream,int)}, * but assumes default to using the Jackson default Base64 variant * (which is {@link Base64Variants#MIME_NO_LINEFEEDS}). * * @param data InputStream to use for reading binary data to write. * Will not be closed after successful write operation * @param dataLength (optional) number of bytes that will be available; * or -1 to be indicate it is not known. Note that implementations * need not support cases where length is not known in advance; this * depends on underlying data format: JSON output does NOT require length, * other formats may */ public int writeBinary(InputStream data, int dataLength) throws IOException, JsonGenerationException { return writeBinary(Base64Variants.getDefaultVariant(), data, dataLength); } /** * Method similar to {@link #writeBinary(Base64Variant,byte[],int,int)}, * but where input is provided through a stream, allowing for incremental * writes without holding the whole input in memory. * * @param b64variant Base64 variant to use * @param data InputStream to use for reading binary data to write. * Will not be closed after successful write operation * @param dataLength (optional) number of bytes that will be available; * or -1 to be indicate it is not known. * If a positive length is given, <code>data</code> MUST provide at least * that many bytes: if not, an exception will be thrown. * Note that implementations * need not support cases where length is not known in advance; this * depends on underlying data format: JSON output does NOT require length, * other formats may. * * @return Number of bytes read from <code>data</code> and written as binary payload * * @since 2.1 */ public abstract int writeBinary(Base64Variant b64variant, InputStream data, int dataLength) throws IOException, JsonGenerationException; /* /********************************************************** /* Public API, write methods, other value types /********************************************************** */ /** * Method for outputting given value as Json number. * Can be called in any context where a value is expected * (Array value, Object field value, root-level value). * Additional white space may be added around the value * if pretty-printing is enabled. * * @since 2.2 */ public void writeNumber(short v) throws IOException, JsonGenerationException { writeNumber((int) v); } /** * Method for outputting given value as Json number. * Can be called in any context where a value is expected * (Array value, Object field value, root-level value). * Additional white space may be added around the value * if pretty-printing is enabled. */ public abstract void writeNumber(int v) throws IOException, JsonGenerationException; /** * Method for outputting given value as Json number. * Can be called in any context where a value is expected * (Array value, Object field value, root-level value). * Additional white space may be added around the value * if pretty-printing is enabled. */ public abstract void writeNumber(long v) throws IOException, JsonGenerationException; /** * Method for outputting given value as Json number. * Can be called in any context where a value is expected * (Array value, Object field value, root-level value). * Additional white space may be added around the value * if pretty-printing is enabled. */ public abstract void writeNumber(BigInteger v) throws IOException, JsonGenerationException; /** * Method for outputting indicate Json numeric value. * Can be called in any context where a value is expected * (Array value, Object field value, root-level value). * Additional white space may be added around the value * if pretty-printing is enabled. */ public abstract void writeNumber(double d) throws IOException, JsonGenerationException; /** * Method for outputting indicate Json numeric value. * Can be called in any context where a value is expected * (Array value, Object field value, root-level value). * Additional white space may be added around the value * if pretty-printing is enabled. */ public abstract void writeNumber(float f) throws IOException, JsonGenerationException; /** * Method for outputting indicate Json numeric value. * Can be called in any context where a value is expected * (Array value, Object field value, root-level value). * Additional white space may be added around the value * if pretty-printing is enabled. */ public abstract void writeNumber(BigDecimal dec) throws IOException, JsonGenerationException; /** * Write method that can be used for custom numeric types that can * not be (easily?) converted to "standard" Java number types. * Because numbers are not surrounded by double quotes, regular * {@link #writeString} method can not be used; nor * {@link #writeRaw} because that does not properly handle * value separators needed in Array or Object contexts. *<p> * Note: because of lack of type safety, some generator * implementations may not be able to implement this * method. For example, if a binary json format is used, * it may require type information for encoding; similarly * for generator-wrappers around Java objects or Json nodes. * If implementation does not implement this method, * it needs to throw {@link UnsupportedOperationException}. */ public abstract void writeNumber(String encodedValue) throws IOException, JsonGenerationException, UnsupportedOperationException; /** * Method for outputting literal Json boolean value (one of * Strings 'true' and 'false'). * Can be called in any context where a value is expected * (Array value, Object field value, root-level value). * Additional white space may be added around the value * if pretty-printing is enabled. */ public abstract void writeBoolean(boolean state) throws IOException, JsonGenerationException; /** * Method for outputting literal Json null value. * Can be called in any context where a value is expected * (Array value, Object field value, root-level value). * Additional white space may be added around the value * if pretty-printing is enabled. */ public abstract void writeNull() throws IOException, JsonGenerationException; /* /********************************************************** /* Public API, write methods, serializing Java objects /********************************************************** */ /** * Method for writing given Java object (POJO) as Json. * Exactly how the object gets written depends on object * in question (ad on codec, its configuration); for most * beans it will result in Json object, but for others Json * array, or String or numeric value (and for nulls, Json * null literal. * <b>NOTE</b>: generator must have its <b>object codec</b> * set to non-null value; for generators created by a mapping * factory this is the case, for others not. */ public abstract void writeObject(Object pojo) throws IOException, JsonProcessingException; /** * Method for writing given JSON tree (expressed as a tree * where given JsonNode is the root) using this generator. * This will generally just call * {@link #writeObject} with given node, but is added * for convenience and to make code more explicit in cases * where it deals specifically with trees. */ public abstract void writeTree(TreeNode rootNode) throws IOException, JsonProcessingException; /* /********************************************************** /* Public API, convenience field write methods /********************************************************** */ /** * Convenience method for outputting a field entry ("member") * that has a String value. Equivalent to: *<pre> * writeFieldName(fieldName); * writeString(value); *</pre> *<p> * Note: many performance-sensitive implementations override this method */ public void writeStringField(String fieldName, String value) throws IOException, JsonGenerationException { writeFieldName(fieldName); writeString(value); } /** * Convenience method for outputting a field entry ("member") * that has a boolean value. Equivalent to: *<pre> * writeFieldName(fieldName); * writeBoolean(value); *</pre> */ public final void writeBooleanField(String fieldName, boolean value) throws IOException, JsonGenerationException { writeFieldName(fieldName); writeBoolean(value); } /** * Convenience method for outputting a field entry ("member") * that has JSON literal value null. Equivalent to: *<pre> * writeFieldName(fieldName); * writeNull(); *</pre> */ public final void writeNullField(String fieldName) throws IOException, JsonGenerationException { writeFieldName(fieldName); writeNull(); } /** * Convenience method for outputting a field entry ("member") * that has the specified numeric value. Equivalent to: *<pre> * writeFieldName(fieldName); * writeNumber(value); *</pre> */ public final void writeNumberField(String fieldName, int value) throws IOException, JsonGenerationException { writeFieldName(fieldName); writeNumber(value); } /** * Convenience method for outputting a field entry ("member") * that has the specified numeric value. Equivalent to: *<pre> * writeFieldName(fieldName); * writeNumber(value); *</pre> */ public final void writeNumberField(String fieldName, long value) throws IOException, JsonGenerationException { writeFieldName(fieldName); writeNumber(value); } /** * Convenience method for outputting a field entry ("member") * that has the specified numeric value. Equivalent to: *<pre> * writeFieldName(fieldName); * writeNumber(value); *</pre> */ public final void writeNumberField(String fieldName, double value) throws IOException, JsonGenerationException { writeFieldName(fieldName); writeNumber(value); } /** * Convenience method for outputting a field entry ("member") * that has the specified numeric value. Equivalent to: *<pre> * writeFieldName(fieldName); * writeNumber(value); *</pre> */ public final void writeNumberField(String fieldName, float value) throws IOException, JsonGenerationException { writeFieldName(fieldName); writeNumber(value); } /** * Convenience method for outputting a field entry ("member") * that has the specified numeric value. * Equivalent to: *<pre> * writeFieldName(fieldName); * writeNumber(value); *</pre> */ public final void writeNumberField(String fieldName, BigDecimal value) throws IOException, JsonGenerationException { writeFieldName(fieldName); writeNumber(value); } /** * Convenience method for outputting a field entry ("member") * that contains specified data in base64-encoded form. * Equivalent to: *<pre> * writeFieldName(fieldName); * writeBinary(value); *</pre> */ public final void writeBinaryField(String fieldName, byte[] data) throws IOException, JsonGenerationException { writeFieldName(fieldName); writeBinary(data); } /** * Convenience method for outputting a field entry ("member") * (that will contain a JSON Array value), and the START_ARRAY marker. * Equivalent to: *<pre> * writeFieldName(fieldName); * writeStartArray(); *</pre> *<p> * Note: caller still has to take care to close the array * (by calling {#link #writeEndArray}) after writing all values * of the value Array. */ public final void writeArrayFieldStart(String fieldName) throws IOException, JsonGenerationException { writeFieldName(fieldName); writeStartArray(); } /** * Convenience method for outputting a field entry ("member") * (that will contain a JSON Object value), and the START_OBJECT marker. * Equivalent to: *<pre> * writeFieldName(fieldName); * writeStartObject(); *</pre> *<p> * Note: caller still has to take care to close the Object * (by calling {#link #writeEndObject}) after writing all * entries of the value Object. */ public final void writeObjectFieldStart(String fieldName) throws IOException, JsonGenerationException { writeFieldName(fieldName); writeStartObject(); } /** * Convenience method for outputting a field entry ("member") * that has contents of specific Java object as its value. * Equivalent to: *<pre> * writeFieldName(fieldName); * writeObject(pojo); *</pre> */ public final void writeObjectField(String fieldName, Object pojo) throws IOException, JsonProcessingException { writeFieldName(fieldName); writeObject(pojo); } /* /********************************************************** /* Public API, copy-through methods /********************************************************** */ /** * Method for copying contents of the current event that * the given parser instance points to. * Note that the method <b>will not</b> copy any other events, * such as events contained within Json Array or Object structures. *<p> * Calling this method will not advance the given * parser, although it may cause parser to internally process * more data (if it lazy loads contents of value events, for example) */ public abstract void copyCurrentEvent(JsonParser jp) throws IOException, JsonProcessingException; /** * Method for copying contents of the current event * <b>and following events that it encloses</b> * the given parser instance points to. *<p> * So what constitutes enclosing? Here is the list of * events that have associated enclosed events that will * get copied: *<ul> * <li>{@link JsonToken#START_OBJECT}: * all events up to and including matching (closing) * {@link JsonToken#END_OBJECT} will be copied * </li> * <li>{@link JsonToken#START_ARRAY} * all events up to and including matching (closing) * {@link JsonToken#END_ARRAY} will be copied * </li> * <li>{@link JsonToken#FIELD_NAME} the logical value (which * can consist of a single scalar value; or a sequence of related * events for structured types (Json Arrays, Objects)) will * be copied along with the name itself. So essentially the * whole <b>field entry</b> (name and value) will be copied. * </li> *</ul> *<p> * After calling this method, parser will point to the * <b>last event</b> that was copied. This will either be * the event parser already pointed to (if there were no * enclosed events), or the last enclosed event copied. */ public abstract void copyCurrentStructure(JsonParser jp) throws IOException, JsonProcessingException; /* /********************************************************** /* Public API, context access /********************************************************** */ /** * @return Context object that can give information about logical * position within generated json content. */ public abstract JsonStreamContext getOutputContext(); /* /********************************************************** /* Public API, buffer handling /********************************************************** */ /** * Method called to flush any buffered content to the underlying * target (output stream, writer), and to flush the target itself * as well. */ @Override public abstract void flush() throws IOException; /** * Method that can be called to determine whether this generator * is closed or not. If it is closed, no more output can be done. */ public abstract boolean isClosed(); /* /********************************************************** /* Closeable implementation /********************************************************** */ /** * Method called to close this generator, so that no more content * can be written. *<p> * Whether the underlying target (stream, writer) gets closed depends * on whether this generator either manages the target (i.e. is the * only one with access to the target -- case if caller passes a * reference to the resource such as File, but not stream); or * has feature {@link Feature#AUTO_CLOSE_TARGET} enabled. * If either of above is true, the target is also closed. Otherwise * (not managing, feature not enabled), target is not closed. */ @Override public abstract void close() throws IOException; }